Not sure how to address this. I decided to punch her off the line last night so I turned off the traction control, waited for the light to go green,and punched her. There was a definite hesitation of about a second, almost like bogging out before it picked up and took off. This is the first modern auto I have owned so is this just a hesitation while the torque converter locks up and would a person actually step on the brake, bring up the RPMS and the launch to avoid this scenario. Or is there something wrong with my truck. I'm not looking for a 1/4 miler here just wanted to see what she'd do in a standing start. Sorry if this is a dumb question.

 

You need to brake torque it a bit. It seems there is some throttle lag programmed into the system. Not that I have ever done this...

 

Definitely normal behavior. First time I tried I had 3 guys in the truck with me. They all kind of looked at me and said something to the effect of, "That's stupid." I learned to hold the brake a little while RPM's rise and then let it loose while adding throttle. You can't just floor it or you get the hesitation.

 

Needs time for the turbo to spool up and once the air hit,,....CYA!!

It's Normal, This is my 3rd diesel and they all do it. What I have noticed is,the hesistation is a lot LESS on the 2011.

Shane

 

Thanks guys, didn't think of the turbo lag to be so noticeable in an auto. Gonna have to try that brake torque method.

 

This is my 1st diesel and I was told it is drive by wire, meaning no throttle cable, and the computer is programmed to do this and help fight emission regulations. This may be bull but I don't know.

I only know when I test drove the 6.0 when it first came out, I mean some of the first ones on the lot, it took off almost as fast as my V10. I've heard that they had to reprogram a lot of these for Job 2 or 3 or whatever.

 

Actually, they don't ALL do it - mechanical diesels have ZERO hesitation! lol My IDI has none, unless you count turbo lag, but thats just a hesitation until max power. It jumps off the line the instant your foot touches the pedal.

Anything computer controlled, including gas motors, have a hesitation while the computer makes calculations needed to properly add fuel, and any other things its doing. I was surprised when I revved up a friend's 7.3L PSD, I could be off the pedal before the RPMs moved!

 

I gotta disagree with that statement.
The computers are way faster than you think. Your brain functions at 23 "frames per second," This is slow compared to the computer.

 

I think dylan is saying the same thing I am, the computer reads all the sensors and adjusts for emission and black smoke control. It's not just the cpm itself, its the time it takes for adjustment to be picked up by exhaust sensors and such.

But again I think there is already built in delays to allow for limited fuel being dumped in, so too much fuel isn't being pumped through that doesn't get burned.

 

If you want to see the tires smoke, just brake torque it

 

that's just plainly incorrect... 23 frames per second is the video rate which your *eyes* can perceive while still noticing the "flicker" - the gaps between frames. Faster than 23 fps and you don't notice it. 23 fps is not how fast your brain processes other things. The human brain controls every organ, muscle, and gland in the body all at once, in perfect harmony. It can do this while performing countless other complex duties as well... the brain is far faster than you give it credit for.

That said, the "throttle lag" is not the computer "making calculations". It is a built-in feature that "softens" drastic changes in throttle input. It's a huge diesel truck... it's not necessarily meant to be "launched" off the line.

All it takes is a new PCM, or at least a reprogram of the existing one. That will change the launch characteristics along with a crapload of other things about the way the truck behaves. It will, however, still have turbo lag. just not as much on this truck as on others - thank the twin-vane turbo for that.

 

I've fought this with a few different electronic throttle vehicles. Regular EFI vehicles with a throttle cable don't have this problem, so i seriously doubt the computer in these newer vehicles has trouble keeping up.
The computer does have to calculate how much "throttle" to give when you move the accelerator, but that's a pretty quick calculation. The delay on mashing the pedal is mostly to prevent an accidental acceleration, if you hit it hard and then release, it just stays at idle.
One trick that works on the Mustangs, and may also work on the trucks, is to turn the key to "on", quickly floor and then release the accelerator, then start.

 

I'm gonna give it a try in about a couple hours, I wish it works but not holding out too much hope.

 

the easiest way around it is to ease into the throttle... do you really need to do burnouts?

seriously though... if you want to get the quickest possible off-the-line response from a stock truck... powerbrake it. hold the brake with your left foot and the gas with your right, enough to get to about 1200 rpm. then when the drag lights hit yellow, off the brake and on the throttle.

 

that's what us boys up north here call brake torque...